File content as of revision 0:464e44ee4534:

#include "mbed.h"
/*
 
 Last chage:    21-03-2014

 Project Name:  NucleoF334R8-DigIN-CRC-DECtoBIN

 By:            www.emcu.it - Enrico Marinoni
 
 NOTE: see here: http://www.emcu.it/NUCLEOevaBoards/NUCLEOevaBoards.html#Tutorial
 
 
    This program show this functionality:
        USART2 (Virtual Com for debug)
        USART1
        DigitalIn
        Decimal to Binary conversion
        CRC calculation
    NOTE:
        A jumper must be present from PB_6 to PA_10 (USART1)
        More details  are available here:
        http://www.emcu.it/NUCLEOevaBoards/mBed/QSG-Mbed-Library.pdf 
        
 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 
  
  VARIABLEs
  
  IO Status -> variable name is: IOStatus
        Name    Bit Directions  Note
        Din1    0   IN          PB_8
        Din2    1   IN          PB_9
        Din3    2   IN          PA_6 - Not used in this release of FW
        Din4    3   IN          PA_7    "       "       "       "   
        RL1     4   OUT         PA_8 Optional 4 Relay shield from SEED STUDIO - Not used in this release of FW
        RL2     5   OUT         PB_10    "       "       "       "       "    -     "       "       "       "   
        RL3     6   OUT         PB_4     "       "       "       "       "    -     "       "       "       "   
        RL4     7   OUT         PB_5     "       "       "       "       "    -     "       "       "       "   
        
  ADC Status - Not used in this release of FW
        Name     Variable Name  Note
        Ain0        ValAin0     PA_0 - Not used in this release of FW
        Ain1        ValAin1     PA_1      "       "       "       "   
        Ain2        ValAin2     PA_4      "       "       "       "   
        Ain3        ValAin3     PB_0      "       "       "       "   
        Ain4        ValAin4     PC_1      "       "       "       "   
        
  
  USART2 (RX==D0 - PA_3, TX==D1 - PA2) it is used for debug (connected to the PC) using TeraTerm.
  USART1 (RX==D2 - PA_10 , TX==D10 - PB_6) it is used for show the way to use another USART.
  Both USART are used in RX Interrupt mode.
  The USART parameters are:
    Baud Rate: 1200 
    Data: 8
    Parity: NONE
    Stop: 1
    Flow Control: NONE        
  
*/          

Serial pc(SERIAL_TX, SERIAL_RX);    // This is USART2 tx, rx
                                    //      It is used for Debug via VirtualCOM 
                                    //      I suggest to use Tera TERM on PC
Serial Serial1(PB_6, PA_10);        // This is USART1 tx, rx

DigitalOut myled(LED1);             // This LED is on NUCLEO-F334R8

DigitalIn BlueButton(USER_BUTTON);  // This is Blue-Button and is on NUCLEO-L153RE
// Digital InPut - from the field
DigitalIn Din1(PB_8);
DigitalIn Din2(PB_9);
DigitalIn Din3(PA_6);
DigitalIn Din4(PA_7);
 
#define Pressed 0
#define NotPressed 1
#define Enable 1
#define Disable 0
#define POLYNOMIAL 0xD8  /* Is for CRC calculation - 11011 followed by 0's */
 
int Car='\0';
int CarSerial1='\0';
int n=0;
int DinStatus = 0;
int ValCRC = 0;


 
// Functions -----------------------------------------------------------------------
void SendToPCtheDinStatusAndCRC(void);

int ReadIO(void);       // Read and return the Din1...4 status

void ConvDecToBin(int); // Convert Decimal number in Binary and send the result
                        //      to the PC 

uint8_t crcNaive(uint8_t const);

void callback2() // PC - USART2 used for Debug
    {
    // Note: you need to actually read from the serial to clear the RX interrupt
    Car = pc.getc();
    }
 
void USART1_INT() // USART1
    {
    // Note: you need to actually read from the serial to clear the RX interrupt
    CarSerial1 = Serial1.getc();
    }

// Interrupt used for flashing the Green Led
Timeout to1;
#define ON 1
#define OFF 0
#define DLYFlash 0.5
int ONOFF_Flashing = ON;
void IntFlash(void);


// MAIN program ---------------------------------------------------------------------
int main() {
    
    // Define the USART ports
    Serial1.attach(&USART1_INT);
    pc.attach(&callback2);

    // SetUp the baud rate
    pc.baud(1200);
    Serial1.baud(1200);    
        
        
    // Set PullUp on Digital Input Pins (Din1...4)
    Din1.mode(PullUp);
    Din2.mode(PullUp);
    Din3.mode(PullUp);
    Din4.mode(PullUp);
 
    // Start flashing the Green Led
    ONOFF_Flashing = ON;              // Enabling flashing flag
    to1.attach(&IntFlash, DLYFlash);  // Enabling flashing Interrupt
    
    
    pc.printf("\n\r\n\r START MAIN - NucleoF334R8-DigIN-CRC-DECtoBIN\n\r");
    
    while(1) // Main infinite loop --------------------------------------------------
    {

    // Test the Blue Button
    if (BlueButton == Pressed)
        {
        while(BlueButton == Pressed)
            {
            if (n == 0)
                pc.printf("Please release the BLUE Button\n\r");
            n++;
            }
        n = 0;
        pc.printf("The Digital Input status are:\n\r");
        DinStatus = ReadIO();
        pc.printf("DinStatus == %x\n\r", DinStatus);
        pc.printf("Din4 Din3 Din2 Din1\n\r");
        ConvDecToBin(DinStatus);            
        
        // CRC calculation
        ValCRC = crcNaive(DinStatus);
        pc.printf("CRC == %d\n\r", ValCRC);
        
        ONOFF_Flashing = OFF;   // Disable Interrupt of Green LED
        
        // Start flashing the Green Led (enable Interrupt)
        ONOFF_Flashing = ON;              // Enabling flashing flag
        to1.attach(&IntFlash, DLYFlash);  // Enabling flashing Interrupt
            
        }
     
        
    // Test the char. received from PC - USART2 that is USB Virtual COM 
    if (Car == 'E')
        {
            pc.printf("\n\r - Send char. E (received from USB_VirtualCOM PC-USART2) to USART1\n\r");
            pc.printf(" - If there is a jumper from PB_6 to PA_10, you will see the Din4...1 status + CRC\n\r");
            Serial1.putc('E');  // Send char. E to USART1
            Car = '\0';
        }
    
    
    if (Car == '?')
        {
            // Send to PC the status of Digital Inputs Din1...4
            SendToPCtheDinStatusAndCRC();    
            Car = '\0';
        }        
    
         
    // Test the char. received from AUREL (USART1)
    if (CarSerial1 == 'E')
        {
            pc.printf("RX char. E from USART1\n\r");
            // Send to PC the status of Digital Inputs Din1...4
            SendToPCtheDinStatusAndCRC(); 
            CarSerial1 = '\0';           
        }
    }
    // END Main infinite loop -------------------------------------------------------
}


void SendToPCtheDinStatusAndCRC(void)
{
    ONOFF_Flashing = OFF;   // Disable Interrupt of Green LED
    pc.printf("\n\r- PC request, to know the Digital Inputs Status\n\r");
    DinStatus = ReadIO();
    pc.printf("DinStatus == %x\n\r", DinStatus);
    pc.printf("Din4 Din3 Din2 Din1\n\r");
    ConvDecToBin(DinStatus);     
    // CRC calculation
    ValCRC = crcNaive(DinStatus);
    pc.printf("CRC related to Din4...1 == %d\n\r", ValCRC);                   
    Car = '\0';
    // Start flashing the Green Led (enable Interrupt)
    ONOFF_Flashing = ON;              // Enabling flashing flag
    to1.attach(&IntFlash, DLYFlash);  // Enabling flashing Interrupt
}


int ReadIO(void)
{
    DigitalIn Din1(PB_8);
    int DinValue=255;
    
    /* Read all the Digital Inputs (Din1...4) and return a DinValue
    
        DinValue (bit)             Note
            0               Din1 - 1 == OPEN, 0 == CLOSE
            1               Din2 -     "         "
            2               Din3 -     "         "
            3               Din4 -     "         "
    */
    
    // Test Din1 status
    if (Din1 == 0)
        DinValue = DinValue & 254; // 0
    else
        DinValue = DinValue & 255; // 1

    // Test Din2 status
    if (Din2 == 0)
        DinValue = DinValue & 253; // 0
    else
        DinValue = DinValue & 255; // 1

    // Test Din3 status
    if (Din3 == 0)
        DinValue = DinValue & 251; // 0
    else
        DinValue = DinValue & 255; // 1

    // Test Din4 status
    if (Din4 == 0)
        DinValue = DinValue & 247; // 0
    else
        DinValue = DinValue & 255; // 1
                                            
    return DinValue;
}

//
// Function that convert a Decimal number in Binary
// the original function is here:
// http://www.programmingsimplified.com/c/source-code/c-program-convert-decimal-to-binary 
//
void ConvDecToBin(int n)
{
    int c, k;
    for (c = 3; c >= 0; c--)
    {
        k = n >> c;
 
        if (k & 1)
            pc.printf("  1  ");
        else
            pc.printf("  0  ");
    }
    pc.printf("\n\r");
}


//
// Function that flashing the Green Led
//    
void IntFlash(void) 
{
    if (ONOFF_Flashing == ON)
        myled = !myled;
    else
        myled = 0;
    to1.detach();
    to1.attach(&IntFlash, DLYFlash); // this line reload Interrupt
}  


//
// CRC calculation
// Original code is gere: http://www.barrgroup.com/Embedded-Systems/How-To/CRC-Calculation-C-Code
//
uint8_t crcNaive(uint8_t const message)
{
    uint8_t  remainder; 


    /*
     * Initially, the dividend is the remainder.
     */
    remainder = message;

    /*
     * For each bit position in the message....
     */
    for (uint8_t bit = 8; bit > 0; --bit)
    {
        /*
         * If the uppermost bit is a 1...
         */
        if (remainder & 0x80)
        {
            /*
             * XOR the previous remainder with the divisor.
             */
            remainder ^= POLYNOMIAL;
        }

        /*
         * Shift the next bit of the message into the remainder.
         */
        remainder = (remainder << 1);
    }

    /*
     * Return only the relevant bits of the remainder as CRC.
     */
    return (remainder >> 4);

}